Note: We are only shredding HDPE and nothing else. As I mentioned in another thread, my STEM students and I won a grant for making a recycling system/station in our classroom. We have almost everything we need.
1. We’ll shred milk jugs and other HDPE bottles.
2. Heat them in the countertop oven (on a cart in the school courtyard).
3. I purchased a 20-ton hydraulic press to press the melted HDPE into blocks.
4. We also used the grant money to purchase a small desktop CNC machine that will be used exclusively with the HDPE blocks we make. Then we’ll create products out of the recycled milk jugs.
But shredding is the obstacle currently. Manually I made a wooden wheel with some weights attached. It works and all the connections are secure (no snapping of pins, etc.), but it gets extremely difficult to hand-crank when the milk bottle bunches up. Lots of reversing and repositioning of the material, which is no big deal with doing it manually. I’m there the whole time for safety and I’m the only one allowed to reach into the chamber.
Anyway, that brings us to this winch. If it’s strong enough to tear through milk jugs and shampoo bottles then we’re all set. I’m not at all worried about continuous running (heat on motor) because we’ll do one bottle at a time and part of the fun is the shredding each student can do.
The winch has buttons for forward and reverse. And I suppose it won’t be too difficult to couple it to the shredder shaft.
Any thoughts? I really appreciate the advice on this forum. I’m very new to all of this.
Thank you.
Mike
PS: I added a photo of our manual crank. It’s okay, but I took it apart. Not good enough because there isn’t enough inertia to get past the harder spots.
I’m tempted by going to a motor too, but if your school has a welder in the shop area, it might be worth fabricating a hand crank with a large flywheel.
There are a few YouTube videos about hand crank shredders. The one I liked (https://www.youtube.com/watch?v=3Q8HE_6JMpU) eventually had a 5:1 gear ratio with a 40 pound, appx 3 foot diameter flywheel. They put the flywheel on the shredder shaft at about 10 RPM, but I’d put it on the crank shaft instead since it runs at 50 RPM. I think they went to chain drive after the belt slipped too much.
I’m working on a pedal powered shredder with a 20″ flywheel of a similar weight, although mine will hopefully be heavier. I anticipate a 90 rpm operational speed at the flywheel, with the shredder rotating at as low as 20 rpm (4.6:1). Bike chains and cogs are great for availability but unfortunately you will be limited to between 13 and 65 teeth unless you gear down in two stages. 65 tooth chainrings, to my knowledge, are only available on Schwinn Exercisers which were made from 1966 to 1982.
I can sympathize with your interest in a motor. But if you decide to continue with human power I’d love to see it. Actually, with a bunch of kids around, why don’t you run it off a capstan? Recess will never be the same.
